Transcript expression and regulatory characteristics of a rice glycosyltransferase OsGT61-1 gene

Glycosyltransferases (GTs) catalyze the reaction of glycosylation of various cellular macromolecules. Rice genome contains 609 potential GT genes which have been grouped into 40 gene families according to CAZy (Carbohydrate Active Enzyme) database. Phylogenetic tree showed that the members of GT61 family are related across genera. Close relationship among various rice GT61 proteins was also reflected from MEME analysis. Full-length cDNA corresponding to MSU rice locus Os02g22380 and encoding for xylosyltransferase was obtained (referred to as OsGT61-1). OsGT61-1 transcript was noted to be ABA- and NaCl-responsive and its expression was more prominent in root than in shoot tissues. Experiments involving fusion of OsGT61-1 promoter (1410 bp upstream to ATG) with GUS reporter gene showed that GUS expression was in consonance with the transcript expression. 1410 bp OsGT61-1 promoter contains two miniature inverted repeat transposable element sequences namely Gaijin (144 bp) and Wanderer (211 bp). Using yeast as trans-host, we noted that these sequences negatively influence the downstream transcript expression.